1. Field of the Invention
The present invention relates to a bevel etching apparatus and a bevel etching method for etching a region at a predetermined distance from an outer edge of substrate.
2. Description of the Related Art
Conventionally, in a manufacturing process for semiconductor devices, a thin film, such as a conductor or an insulator, is formed on the surface of a semiconductor substrate, on which pattern transfer is performed. At this time, when the pattern transfer is performed even to a substrate periphery (a bevel), a pattern may become separated from the semiconductor substrate and may become particles. This is because the pattern is easily peeled off at the bevel. When these particles are re-deposited onto the semiconductor substrate, re-deposition reduces the production yield of semiconductor devices. Consequently, after a thin film is formed over the entire region of the surface in the semiconductor substrate, treatment is performed to remove unnecessary portions of the thin film, i.e., the thin film formed at the bevel.
A method of removing film by polishing the bevel with CMP (Chemical Mechanical Polishing) and another method to clean the bevel using wet etching are mainly used for bevel etching apparatuses (reference is made, for example, to Publication of Japanese Patent Application Laid-Open No. 2002-9059).